The present invention relates to a tacky attachment for adhering a cover to a stent and to a method for adhering a cover to a stent.
Stents are typically implanted within a vessel in a contracted state and expanded when in place in the vessel in order to maintain patency of the vessel to allow fluid flow through the vessel. Implantation of stents is typically accomplished by mounting the stent on a balloon portion of a catheter, positioning the stent in a body lumen and expanding the stent to an expanded state by inflation of a balloon within the stent. The stent is left in place by deflating the balloon and removing the catheter.
Stents typically have a metallic structure to provide strength which is required to function or to support a stent. However, metals do not provide for delivery of localized therapeutic pharmacological treatment of a vessel at the location being treated within the stent.
Polymeric materials capable of absorbing and releasing therapeutic agents typically do not fulfill structural and mechanical requirements of a stent, especially when the polymeric materials are loaded with a drug, since the drug loading of a polymeric material significantly affects the structural and mechanical properties of the polymeric material.
U.S. Pat. No. 5,637,113, which issued Jun. 10, 1997, to Tarataglia et al. describes a metallic stent which is wrapped with a polymer film. The polymer film is capable of carrying and releasing therapeutic agents. The polymeric film is secured to the metallic stent by a mechanism such as an adhesive bonding. The adhesive is a copolymer of poly-L-lactic acid (L-PLA) and polycaprolactone (PCL). Other adhesives, heat bonding, solvent bonding and one or more mechanical fasteners, such as a metal clip are also suitable.